1. Field of the Invention
This invention relates to an apparatus for the selective application of liquid media to various surfaces. In particular, but not exclusively, the invention relates to an apparatus that can be utilized to apply liquid chemicals to the foliage of vegetation.
The maintenance of vegetation often includes spraying the foliage with liquid chemicals which may include nutrients, fertilizers, fungicides and the like. The disadvantage with such an operation is that a considerable amount of the chemicals can be lost such as through spray drift and because a spray is generally non-selective, a proportion of the spray will not be applied to the foliage. Consequently, there is a significant wastage with such type of application. Spraying of foliage with chemical herbicides and the like is often used for the control of vegetation and such sprays are extensively used in various areas and applications. There is an increasing concern with the practice of using sprays containing herbicides and other noxious chemicals because of the perceived environmental damage from over spray and from spray drift. It is apparent that other means of applying the chemicals which will minimize such damage would have a general acceptance.
In an endeavor to control over spray and minimize spray drift, various forms of apparatus have been proposed in the past which do not utilize a spray but instead apply a liquid media or a liquidized substance directly to the foliage of vegetation. By this method the actual amount of the liquid or liquidized substance can be more precisely controlled as can the actual application of the liquid or liquidized substance to select vegetation.
2. Description of the Prior Art
One system which is designed to apply a chemical solution to vegetation by direct contact is disclosed in New Zealand Patent Specification 147753. The apparatus described in that specification comprises two cylinders which are mounted in a frame which is attachable to a tractor. The cylinders are covered with a sponge-like material which is kept wet by a chemical solution which is applied to the surface of the cylinders. The cylinders rotate in a manner that as the tractor moves along the ground, the cylinders are held above the ground so that only the surface of the cylinders will touch the foliage of weeds without touching the grass or clover beneath the weeds. The chemical is thereby transferred onto the foliage.
Yet another apparatus for directly applying a chemical solution to foliage is disclosed in New Zealand Patent Specification 231420 which describes an applicator roller supported by a ground wheel. A chemical solution is applied to the surface of the roller and the roller is maintained above the ground by the ground wheel so that as the apparatus moves over the ground, the chemical solution on the surface of the roller is applied to the foliage which is contacted by the roller.
Another form of applicator which is designed more particularly but not exclusively for manual use, that is, the applicator is held by the operator rather than the applicator being attached to and forming part of the apparatus of a tractor or the like, is described in British Specification 1085635. That specification discloses a cylindrical roller which has a porous surface. The roller is mounted for rotation on a pipe which is oriented so that in use the longitudinal axis of the roller will lie substantially parallel to the ground. Holes are formed in the wall of the pipe so that liquid media can be passed into the pipe and through the holes in the pipe to charge the porous surface of the cylinder. To spread the liquid media, the roller is propelled in a manner that the surface of the roller will contact the foliage and transfer the liquid media to the foliage. The specification discloses that as the roller passes over the foliage, the porous surface of the roller will be compressed and after it has passed over the foliage, the porous surface will expand which results in a pumping action which facilitates the transport of the liquid media from the interior of the roller to the outer circumference. The roller as disclosed is also provided with end pieces of a solid material which will act as wheels to prevent excess radial compression of the porous surface of the roller.
Another form of applicator is disclosed in U.S. Pat. No. 3,651,600 which describes a drum which can be a length of plastic pipe, with the drum being covered by an absorbent material which is charged with a herbicide through openings in the wall of the pipe. The ends of the drum are provides with wheels which are of a greater diameter of the drum so as the drum rolls over the ground, the outer surface of the drum will be out of contact with the ground but can still contact the foliage.
A still further form of applicator is disclosed in New Zealand Patent Specification 286054 where the apparatus comprises a rotary applicator which has rotary movement within an applicator head. The apparatus is provided with a reservoir so that chemical solution can flow through a flow resisting means and a wick onto an absorbent surface of the rotary applicator.
It is therefore an object of this invention to provide an improved applicator for dispensing liquid media onto foliage and the like which does not exhibit any of the disadvantages of the prior known systems and which will at least provide the public with a useful choice.